Critics maintain that such verification is impossible, due to a misunderstanding about the nature of the universe.

Cockcroft and Walton "did not see their experiments as a test of Einstein's mass-energy relationship; rather, they simply used that relationship in their analysis, assuming it to be valid "[3] The first to stress this aspect of the experiment was the eminent physicist Kenneth Bainbridge in 1933:

The gain in energy in the reaction is 16.97×106 e-volts, an energy equivalent to 0.0182 mass units on the O16 scale if ΔE =C²Δm. Taking Aston's values for the mass of helium and hydrogen and the author's value, 7.0146±0.0006 for Li7, the mass change is 0.0181 ± 0.0006 in the reaction which may be represented as Li7 + p → 2α. Within the probable error of the measurements the equivalence of mass and energy is satisfied. --Kenneth Bainbridge

Neither the Nobel Prize committee nor the prize recipients made the claim that their experiment verified of Albert Einstein's famous E=mc² formula.[4][5]